Berberine
supplementA plant compound sold as a supplement for blood sugar and weight. It is not a GLP-1 drug.
13 providers
No. 064supplement
Magnesium citrate
Magnesium citrate is a supplement that is sold over the counter.
Also known as Magnesium, citrate of magnesia
Magnesium citrate pairs magnesium with citric acid. NIH notes citrate is among the forms the body absorbs better than oxide or sulfate. In larger amounts it draws water into the bowel, which is why the liquid form is sold as an over-the-counter laxative for occasional constipation.
Is Magnesium citrate FDA-approved?
Sold without a prescription. Supplements are not reviewed by the FDA before sale, so third-party testing matters. Sold without a prescription: as a dietary supplement, and as an FDA-regulated over-the-counter saline laxative (oral solution) for occasional constipation.
As of October 7, 2026.
Key takeaways
- Magnesium citrate is one of the better-absorbed forms of magnesium, sold as a supplement and as an over-the-counter laxative.
- The liquid laxative is meant for occasional constipation and usually works within half an hour to 6 hours.
- Too much causes diarrhea and cramping, and people with kidney disease should ask a doctor first.
- Guidelines for chronic constipation studied magnesium oxide, not citrate, and rate the evidence as very low certainty.
How does Magnesium citrate work?
As a nutrient, magnesium supports hundreds of enzymes involved in muscle, nerve and energy function. NIH notes the citrate, aspartate, lactate and chloride forms tend to be absorbed better than oxide and sulfate.
In larger amounts, unabsorbed magnesium holds water in the bowel by osmosis. That softens stool and triggers a bowel movement, which is how the saline laxative works and why diarrhea is the first sign of too much.
Magnesium citrate vs glycinate: which is better?
They suit different goals. NIH lists citrate among the forms absorbed better than oxide and sulfate, and magnesium is a key ingredient in some laxatives, so citrate is the usual choice when a gentle laxative effect is wanted. NIH ODS: Magnesium fact sheet for health professionals
Glycinate is popular for daily use because many people find it easier on the stomach, though NIH does not single it out as better absorbed. Either form counts toward NIH's upper limit for magnesium from supplements. NIH ODS: Magnesium fact sheet for consumers
What does the evidence say about Magnesium citrate?
Moderate human evidenceIts laxative effect is well established on the OTC label. Evidence for sleep or other benefits in people who are not low in magnesium is limited, and constipation guidelines studied magnesium oxide rather than citrate.
What to expect
What trials and prescribing information measured over time. Everyone responds differently.
- Half an hour to 6 hours
The OTC laxative label says it generally produces a bowel movement within this window.
- Beyond a week
The label says not to use a laxative for more than a week unless a doctor advises it.
What do clinicians say about Magnesium citrate?
Clinicians treat magnesium citrate as a familiar over-the-counter option for occasional constipation and a reasonable way to add magnesium, with caution in kidney disease.
The OTC Drug Facts say the oral solution relieves occasional constipation and generally produces a bowel movement in half an hour to 6 hours.
DailyMed: Magnesium citrate oral solution, OTC Drug FactsThe label says to ask a doctor first with kidney disease, a magnesium-restricted diet, stomach pain, nausea or vomiting, or a sudden change in bowel habits lasting over 2 weeks, and not to use a laxative for more than a week without advice.
DailyMed: Magnesium citrate oral solution, OTC Drug FactsThe 2023 AGA-ACG constipation guideline conditionally suggests magnesium oxide on very low certainty evidence and advises avoiding it with kidney insufficiency because magnesium can build up.
AGA-ACG clinical practice guideline: pharmacological management of chronic idiopathic constipation (2023)NIH warns that very high magnesium intakes from supplements or medicines can cause irregular heartbeat and, rarely, cardiac arrest.
NIH ODS: Magnesium fact sheet for health professionals
Summaries of published guidelines, drug labels, regulators and reviews, each attributed to its source. DiscoverMedica does not employ clinicians.
Is Magnesium citrate right for you, and who should avoid it?
Often considered for
- Adults with occasional constipation (the OTC laxative use)
- People with low dietary magnesium who tolerate a well-absorbed form
Not a fit, or needs extra care
- Kidney disease or a magnesium-restricted diet, without a doctor's advice
- Stomach pain, nausea or vomiting, or rectal bleeding (seek care instead)
- People taking bisphosphonates or tetracycline or quinolone antibiotics should space them apart
Only a licensed clinician who knows your history can decide whether it is right for you.
What are the risks and side effects of Magnesium citrate?
- Diarrhea, nausea and cramping are the usual signs of too much; very high intakes can cause dangerous heart rhythm problems.
- People with kidney disease or a magnesium-restricted diet should ask a doctor first, because magnesium can build up.
- Space it apart from bisphosphonates and tetracycline or quinolone antibiotics; diuretics and acid reflux drugs change magnesium levels.
- The laxative label says not to use it for longer than a week without asking a doctor, and to stop for rectal bleeding.
What should you ask a clinician about Magnesium citrate?
- Is magnesium citrate or another option better for my constipation?
- Is it safe with my kidney function and medicines?
These save with the compound when you add it to My Journal, so they’re on the printout for your visit.
How do people buy Magnesium citrate?
No prescription is needed. Supplement brands and retailers sell it online and in stores.
Check with a clinician or pharmacist first if you take prescription medication or have a chronic condition.
Choose a product with independent testing, such as NSF Certified for Sport or USP Verified, because FDA does not check supplements before they are sold.
Where some people buy it
- ThorneSells a magnesium citrate powder direct to consumers.
- Life ExtensionSells magnesium citrate capsules direct.
- iHerbCarries magnesium citrate from many brands.
From each provider’s own site, checked October 7, 2026. Programs change, so confirm the details before you sign up.
Where can I get Magnesium citrate?
13 providers list Magnesium citrate on DiscoverMedica, lowest listed price first.
$9.50listed price†
Buy at Life Extension $14.19listed price†
Buy at Nature Made $20.50listed price†
Buy at Pure Encapsulations † Prices as listed by the provider when we checked; they change.
Magnesium citrate: questions, answered
What are the side effects of magnesium citrate?
NIH says high intakes of supplemental magnesium cause diarrhea, nausea and abdominal cramping, and very high intakes can cause an irregular heartbeat. As a laxative, cramping and loose stools are expected. People with kidney disease are at risk of magnesium building up. Stop and ask a doctor if there is rectal bleeding or no bowel movement after use.
How fast does magnesium citrate work for constipation?
The OTC Drug Facts for the oral solution say it generally produces a bowel movement in half an hour to 6 hours. It is labeled for occasional constipation only. If you need a laxative for more than a week, or your bowel habits change suddenly for more than two weeks, the label says to ask a doctor.
Is magnesium citrate or glycinate better?
It depends on the goal. NIH lists citrate among the better-absorbed forms, and its laxative effect makes it the common choice for occasional constipation. Glycinate is often chosen for daily use because many people find it gentler on the stomach. Both count toward NIH's upper limit for magnesium from supplements.
Can I take magnesium citrate every day?
As a laxative, the label says not to use it for more than a week without a doctor's advice. As a supplement, NIH sets an upper limit for magnesium from supplements, and diarrhea is the usual sign of going over it. People with kidney disease, or who take antibiotics, bisphosphonates or diuretics, should ask a clinician first.
Important safety information
Key risks
- Diarrhea, nausea and cramping are the usual signs of too much; very high intakes can cause dangerous heart rhythm problems.
- People with kidney disease or a magnesium-restricted diet should ask a doctor first, because magnesium can build up.
- Space it apart from bisphosphonates and tetracycline or quinolone antibiotics; diuretics and acid reflux drugs change magnesium levels.
- The laxative label says not to use it for longer than a week without asking a doctor, and to stop for rectal bleeding.
Talk to a clinician first, or avoid it, if
- Kidney disease or a magnesium-restricted diet, without a doctor's advice
- Stomach pain, nausea or vomiting, or rectal bleeding (seek care instead)
- People taking bisphosphonates or tetracycline or quinolone antibiotics should space them apart
This is not a complete list of risks. Talk to a licensed clinician or pharmacist about your own situation. If you have a severe reaction, call 911. You can report side effects to the FDA through MedWatch at 1-800-FDA-1088.
Sources
- NIH ODS: Magnesium fact sheet for health professionals
- DailyMed: Magnesium citrate oral solution, OTC Drug Facts
- AGA-ACG clinical practice guideline: pharmacological management of chronic idiopathic constipation (2023)
Also checked for this guide
- NIH ODS: Magnesium fact sheet for consumers
- National Kidney Foundation: Safe medicine use in chronic kidney disease
Guide reviewed October 7, 2026.
Educational information only, not medical advice. It does not replace a conversation with a licensed clinician.
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